Despite poor infrastructure in many areas, India has one of the best telecom infrastructure thanks to Sam Pitroda - the father of Indian telecom. From Wikipedia [1]:
"As technology Advisor to the Prime Minister, Rajiv Gandhi in the 1984s, Pitroda not only heralded the telecom revolution in India, but also made a strong case for using technology for the benefit of society through missions on telecommunications, literacy, dairy, water, immunization and oil seeds."
Getting a SIM card is intentionally hard partly due to their prevalence for terrorist activities (especially in its initial days when anyone could simply buy a SIM card from a store without any ID proof) and partly from the lack of a centralized electronic citizen identification system similar to SSN.
[1]: http://en.wikipedia.org/wiki/Sam_Pitroda